use bytes.Equal() instead, Thanks for Thomas' suggestion

go/storage/volume.go

@@ -1,6 +1,7 @@
 package storage
 
 import (
+	"bytes"
 	"errors"
 	"fmt"
 	"io"
@@ -166,13 +167,7 @@ func (v *Volume) isFileUnchanged(n *Needle) bool {
 		}
 		oldNeedle := new(Needle)
 		oldNeedle.Read(v.dataFile, nv.Size, v.Version())
-		if len(oldNeedle.Data) == len(n.Data) && oldNeedle.Checksum == n.Checksum {
-			length := len(n.Data)
-			for i := 0; i < length; i++ {
-				if n.Data[i] != oldNeedle.Data[i] {
-					return false
-				}
-			}
+		if oldNeedle.Checksum == n.Checksum && bytes.Equal(oldNeedle.Data, n.Data) {
 			n.Size = oldNeedle.Size
 			return true
 		}